MKKRIAM: TRIASSIO 1C! ITII VOSAIMUA. 141 



The pelvic elements seen in specimen 9608 (pi. 16) are much like those of 

 Delphinosaurm pcrrini, though the pectoral arch is very different. The ilium 

 is more robust than in Toirtoominix. The proximal end is broadened trans- 

 versely much as in D<'li>lihio*(uu-nx and Cymbospondylus. There is no evi- 

 dence indicating the presence of a posterior tubercle such as seems to be present 

 on the ilium of Delphinosawrus. 



The ischium is a broad, plate-like element, but is not as wide as in Delj>lii- 

 itvMtiiriis or in Cymfoospondylus }>< : lrinns. 



The pubis is intermediate in form between that of the 6'. jHtcifictts and the 

 corresponding element of I), perrini. It differs from the pubis of S. pacificus 

 in the form of the posterior portion of the proximal end, which in S. pacificus 

 curves inward and forward toward the posterior hook of the expanded distal 

 portion. In the type specimen of S. pacificus the proximal end is broader and 

 the posterior proximal hook more pronounced than in specimen 9608. 



Of the left hind limb (pi. 16, fig. 6) the elements belonging to the propo- 

 dial and epipodial segments are but little disturbed. The femur is a short 

 robust bone with a well developed trochanteric ridge, and a somewhat ex- 

 panded distal end. It is a little more slender than in D. perrini, but is not more 

 elongated than in Ichthyosaurus. It is relatively heavier and broader than in 

 Cytn-bospondijlits. 



Each of the epipodial elements shows a median constriction, and they are 

 in consequence of this separated by a wide gap. The tibia is much larger than 

 the filmla, and is almost equally expanded at the two ends. The fibula is much 

 expanded distally, while the proximal end is hardly broader than the median 

 portion of the shaft. The characters of the epipodial elements are in general 

 much like those of DcfpliinosduriiN )>cn-ini excepting that both elements are a 

 little more slender than in that form. With the determinable limb bones of 

 this species are several discoidal limb elements which may represent tarsals or 

 possibly phalanges. In one of these rounded elements the thickness of one side 

 is much greater than the other, probably indicating its position near the border 

 of the limb, and the peripheral surface is distinctly concave". 



.MEASUREMENTS OF SPECIMEN 9608. 



Pelvic Elements. 



Ilium, length . HO mm. 



Ilium, transverse diameter of distal end 60 



Ischium, length 



Ischium, greatest width 85 



Pubis, length - 120 



Pubis, greatest width of distal blade - 105 



Pubis, width of proximal end 67 



